Vented closure



0611. 7, 1969A g.-R .|$TVONE 3,471,051

' VENTED cLosuRE 4Filed June 26, 1968 INVENTOR DAVID n. c|sToNe ,BY Q` A'rro'RNEY United Parent l 3,471,051, .f vENTEncLOsURE .l David R. Cistone, Lancaster, Pa.,"assgnor`to Armstrong Cork Company, Lancaster, Pa., a 'corporation of Pennsylvaniav v f' Y Filedl June26, 1968, Ser. No. 740,157 l Y. Int. Cl.-B65d,51/]6 i U.S. Cl. 215f40,y V i .p 3Claims ABSTRACT OF THE: DISCLOSURE A self-venting closure-for containers which tends to buil-d up internal vaporypressure. Containers ottenicarry liquids which, due to storage in iwarmplaces, exposure to i 3,471,051 yPatented Oct. 7, 1969 Ice 2 Y :SUMMARY oF THE INVENTION i terial to protect it against deterioration by the contents of the container and contamination of the contents of the container by the liner material. The facing material 1s completely impervious to liquid and gas.

It is proposed to use in a closure a beater-saturated,

' asbestos-fiber lining material iny lieu of thepulpboard 1insunlight or Isubjection to agitation, will-build up internal vapor pressures within thecontainer in whichithey are coninedi The liner vfor the selfwenting closure cap permits the escape of gas to relieve the internal buildup' of pres'- sure. The liner is composed of an vasbestos-ber backing with a facing of brous, semi-permeable, spun-bonded polyethylene which permits the passage of gases, but is not destroyed by liquid wetting Iand greatly inhibits the l passage yof liquid.

CROSS REFERENCE TO RELATED APPLICATION The self-venting closure herein is fan improvement over the closure of application Ser. No. 739,321 tiled June 26, 1968 in the name of Gerald L. Roy.

BACKGROUND OF THE INVENTION Field of the invention Description of the prior art Numerous venting structures are available for relieving the stress pressure buildup within a container. Patent No. 2,424,801 discloses one type of venting st-ruc-ture wherein the glassware neck is provided with a special configuration which will permit gas to escape after the gas buildup has reached a point where it will lift the liner off the neck of the glassware.

Patent No. 3,114,467 discloses another type of selfventing bottle cap wherein the bottle cap is provided with a special structure which permits the Iliner to riseup under the action of the buildup of gas pressure. The raising of the liner away from the neck of the glassware then permits the gas to escape. These above structures currently available on the open market suffer from one major deiiciency. While the structures will permit gas to escape, they are also equally suitable for permitting liquid to escape. Turning of the bottle upside down will permit the liquid to fact -on the venting struct-ure 'and escape in the same manner as the gas would escape. This limitation makes the product very ldiil'icult lto maintain from a packing and shipping point of view since the container must always be maintained in its upright position or else there will be leakage. The self-venting closure herein differs from the closure of the :above-mentioned application in that la facing material of substantially less expense is used and the pulpboard backing has been replaced with an :asbestos-ber backing which is particularly resistive to attack by bleach.

The primary object of the self-venting closure herein is to provide a structure which will permit bleach bottles to vent, but prevent the deterioration of the liner due to any wetting of the liner by bleach.

ing'm'aterial and to replace entirely or in part the conventional impervious facing material with a fibrous, spunbonded, semi-permeable polyethylene. The lining material and the facing will be of the same relative thickness as the conventional materials. The new facing material is semi-permeable in that it will permit the passage under normal circumstances of gas, but will prevent normally the passage of liq-uid. However, there may be a slight wettingv of the liner material by the liquid contained within the container. The beater-saturated asbestosdiber lining material Will not be affected by |any liquid wetting and this material is capable of permitting the passage of gas. Consequently, the excess pressure due to gas is relieved by the gas passing lthrough the facing material, the lining material land 'out around the threads of the closure to the atmosphere.

BRIEF DESCRIPTION OF THE DRAWING The single tigure of the drawing is a cross-sectional view of the clos-ure with .a liner mounted on the neck of the container.

DESCRIPTION OF THE PREFERRED EMBODIMENT The neck 2 of la conventional container has -a substantially flat upper surface 4 against which the liner presses to form a liquid-tight seal. Threads 6 on the container engage with threads 8 of .a conventional closure 10. The closure has fa `lining 12 which is compose-d of a lining material 14 and facing 16. The use of Ia two-part liner with a closure is conventional in the ar-t as shown in Patent No. 2,359,924. The difference over the prior art is that the facing material 16 is not the conventional nonporous sheet material normally used as 'a facing. It is proposed to use |a fibrous, spinbonded polyethylene as Ia facing material. An example of a spun-bonded polyethylene available for use is the material sold under the trade name Tyvek by du Pont Company, Inc. Tyvek is :a material composed of randomly rar-ranged, continuous lament li'bers which are spun by textile -ibers and heat sealed to one another to form a web. The material forms a membrane which has the ability under normal operating conditions to permit the passage of gas, but to prevent the passage of liquid. As such, it functions as a semiHperr'neable membrane. However, it as been found that this material, when used with bleach or other corrosive liquids, has a tendency to permit wetting of the backing material, and the corrosive liquids 'attack the backing material causing its deterioration.

Consequently, instead of using the conventional pulpboard lining material :as Ia backing, a beater-saturated, fasbe-stosiber felt has been used ,as the lining material.

An acceptable liner 'has been formed by using an asbestos sheet material sold under the tra-de name Hydrocord lby Armstrong Cork Company `an-d fully described in Patent No. 2,759,813. This asbestos-fiber sheet is then covered with a facing of spun-bonded polyethylene which has 'a thickness of 4 to 9 mils and a denier per ilament of less than 1. As indicated above, the l-ining material is the 'commercially available Hydroc'ord and the facing is the commercially `available Tyvek. Tests with this liner have Ishown that this particular structure readily vents the buildup of internal pressure within the bleach bottle, but the semi-permeable Imembrane .facing prevents the bleach liquid from leaking past the facing when the bleach lbottle is upside down. What minor wetting of the lining material that may occur to the lining material is ineffective t-o damage the lasbestos-fiber lining material. Consequently, the lining material is able to Iresist `deterioration and continue its function as the backup for the facing to maintain the seal between the flat surface on the top of the neck of the bottle `and the inside of the closure. Maintenance of the eiectiveness of the liner thus prevents the bleach from working its Way past the liner to -d'rip down the outside surface of the 'bottle and attack the bottle label, the packing case carrying the bottle or the shelf supporting the bottle in the store.

What is claimed is:

1. A self-venting closure cap for a container having a threaded neck portion presenting a circular rim, said cap including a 'cap body having a crown portion :and a depending -internally threaded skirt `design for threaded engagement with the threaded neck portion of the container, the inside Iface of the crown portion of the cap receiving a liner composed of an asbestos-fiber lining material at least partly face-d with a ibrous, spun-bonded sheet material which constitutes -a means for vent-ing the internal gas pressure Ibuildup Within the container lwhile at the same time preventing the pass-age of liquid past :the facing material.

2. The self-venting closure cap of claim 1 Iwherein the lining material is a beater-saturated', asbestos-felt sheet and the facing material is Icomposed of randomly arranged continuous filament fibers which are spun-like textile fibers and heat sealed .to one another to forma web.

3. The self-venting closure cap of claim 2 wherein the cap is used in combination with a container containing bleach.

References Cited UNITED STATES PATENTS 3,071,276 1/1963 Pallet-t et al. 2l5-56 l l FOREIGN PATENTS 1,470,680 1/1967 France.

GEORGE T. HALL, Primary Examiner U.S. Cl. X.R. 215--5 6 

